The experts tasked with delivering Europe's green energy revolution have said that a lack of political leadership is their biggest single obstacle in meeting the continent's ambitious targets for renewable power.

At a meeting of more than 100 leading European engineers this week, half said that, while the technology already exists to deliver 20% of all of the EU's primary energy from renewables, governments are slow to pass legislation that would enable it to be introduced quickly.

The engineers, representing 21 European countries, came together under the auspices of the Royal Academy of Engineering (RAEng) in London to discuss the technical challenges in meeting Europe's renewables challenges. When asked to choose the single biggest potential stumbling block, 50% chose a lack of political will.

Consumer behaviour came next but it was far behind the political problem, topping the list for only 19% of the engineers. The next biggest issue was the lack of suitable government incentives for generating renewable power, chosen by 13% and then insufficient capacity in electricity grids with 9%.

Despite the problems, 66% of the expert group felt the EU's 2020 targets could be achieved with a concerted effort.

"There is today a diversity of views of energy security and how serious climate change is," said Jan van der Ejik, chief technology officer at Shell. "That translates to a lack of political resource."

That lack of leadership has fed into a shortage of suitable incentives that could shepherd new technologies into the crowded energy market. The engineers highlighted the example of feed-in tariffs, which pay electricity generators a guaranteed premium price for the power they produce from renewable sources. While these tariffs have accelerated the introduction of solar technology in Germany and wave power in Portugal, the same is not true for the UK.

The Energy Bill, currently making its way through the British parliament, does include an amendment to introduce feed-in tariffs, but environmental campaigners have argued that the government's proposals are too weak.

The experts at the RAEng meeting questioned whether the EU should maintain its commitment to raise its renewable energy target to 30%, if a successor to the Kyoto protocol was agreed next year: 72% of the group felt the rise was unecessary.

"It's much more important that we cut CO2 emissions than raise the targets for new renewables sources," said Irene Aegerter, vice president of the Swiss Academy of Engineering Sciences. "We don't need to go to 30% but we have to include all potential CO2-free energy sources like nuclear."

Others at the meeting agreed that the EU should only set a carbon-reduction target and then let countries individually decide how to reach it, whether by renewables technology or approaches such as energy efficiency. Technologies that increase efficiency are the best, said Paul Caseau of the National Academy of Technologies of France. "Society is quite ready to use them, they are not extremely expensive and they can be used for a long time. If you do only one thing, then you do only that."

Efficiency technologies were seen by 24% of the engineers as one of the top three ways, after renewables, to reduce CO2 emissions. Nuclear power was seen as a priority by 21% of the expert group and carbon capture and storage (CCS) technology by 18%. "Even as far out as 2050, fossil fuels are still accounting for two-thirds of the energy supply," said Van der Ejik. "What needs to be done is find real progress in CCS – it's only if we tackle that source of CO2 that we can hope to bring emissions down."

There was also majority support for the construction of a pan-European energy supergrid: 86% of the engineers thought it a good way to balance out the intermittency of renewable power sources across the continent. The grid could be fed, for example, by solar power plants in southern Europe and the Sahara region and with wave, tidal and biomass plants across the north of the continent. It would allow countries such as the UK and Denmark to export wind energy at times of surplus supply, as well as import from other green sources such as geothermal power in Iceland.

The European supergrid plan already has tentative support from politicians, including Nicolas Sarkozy, who commissioned a study earlier this year into whether such a renewable energy grid would be feasible. The engineers at the RAEng meeting said that any European grid plan should include not only strengthening the existing national grids, so that they can carry more power, but also the construction of a new backbone of high-voltage direct current (HVDC) transmission lines, which can carry electricity long distances without losing as much power as standard alternating-current lines.